Previously individual test strips have been used in practice for the self-diagnosis of diabetics which are photometrically analyzed after applying a small amount of sample in order to determine the glucose content in the sample (blood or tissue fluid) as accurately and reliably as possible. In order to improve the user-friendliness it has already been suggested that a plurality of tests be provided on a test tape in the form of a tape cassette. It should be possible to insert such tape cassettes as a disposable part into compact hand-held devices in order to enable all required analytical steps to be carried out automatically and rapidly.
Designs for a reversing lock to prevent tape unwinding is generally known, in order to prevent unintentional winding out of used tape contaminated with blood. One exemplary design is disclosed in U.S. Publication No. 2006/0240403. Generally, a lock is provided that allows test tape to be wound forward whereas it should be secured against turning back in the opposite direction of rotation. In this connection it should be noted that diagnostic tape cassettes as consumable parts are mass-produced articles which it should be possible to manufacture as simply as possible and should operate reliably with a high degree of user friendliness.
On this basis the object of the invention is to further improve the test tape systems proposed in the prior art and to achieve particular advantages for their use while being simpler to manufacture.